This invention relates to a tape cassette and, more particularly, to a reel leaf spring attached to the underside of a tape cassette cover for rotatably supporting the hubs of the tape reels mounted on the tape cassette base.
Conventionally, as described in U.S. Pat. No. 4,368,860, a video tape cassette includes, among other things, a "coined" reel leaf spring, i.e., a spring stamped from a flat piece of stainless steel, such that arms are formed to extend from both sides of a central, flat portion. The reel leaf spring is fixed to the underside of the tape cassette cover at the central flat portion via holes formed therein which receive corresponding projections formed on the center of the cover which are then caulked or swedged. The arms extending from the central flat portion are preliminarily bent at an angle, such as 5.degree.-30.degree.. In this way, the arms of the reel leaf spring protrude downward, away from the underside of the cover.
With the arrangement described above, when the cover, including the reel leaf spring, is assembled with the tape cassette base in a known manner, both of the free ends of the arms of the reel leaf spring contact the hubs of the respective tape reels and bias the tape reels downwardly, so that the tape reels are rotatably retained in position.
The conventional coined reel leaf spring described above necessarily requires a thickness of approximately 0.012 of an inch to effect the required bending and to maintain the biased relationship against the hubs throughout the useful life of the video tape cassette.
A major drawback of this conventional leaf spring is that the required thickness of the metal used to make the reel leaf spring results in a relatively high material cost, thus making overall production costs for the tape cassette high. Accordingly, the prior art discussed above still does not teach a coined reel leaf spring which is capable of producing the most cost-efficient video tape cassette.